Patent US4954870A successfully refreshed from Google Patents.
US4954870A
Expired / Lapsed
US
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Semiconductor device
Assignee: Toshiba Corp
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Filing: 1985-12-05
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Granted: 1990-09-04
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Expires: 2005-12-05
Abstract
Abstract Semiconductor device in which a semiconductor chip is fixed to a lead frame by Sn-Cu alloy solder with a first metal layer interposed between the chip and the solder. The first metal layer is formed at a thickness ranging from 2000 ANGSTROM to 3 mu m, and made of a metal selected from Ti, Cr, V, Zr, Nb and an alloy containing at least one of these metals. A second metal layer made of Ni, Co or an alloy containing at least one of these metals may be interposed at a thickness smaller than that of the first metal between the first metal layer and the solder.
Inventors
- 👤 Momoko Takemura
- 👤 Michihiko Inaba
- 👤 Toshio Tetsuya
- 👤 Mitsuo Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:26
CPC Classifications
B; B23; B23K; B23K35/00; B23K35/001; B23K35/22; B23K35/24; B23K35/30; B23K35/302; H; H10; H10W; H10W70/00; H10W70/20; H10W70/24; H10W72/00; H10W72/30; B23K2035/008; H10W72/01; H10W72/013; H10W72/01331; H10W72/071; H10W72/073; H10W72/07331; H10W72/07336; H10W72/351; H10W72/352; H10W72/50; H10W72/541; H10W72/5449; H10W72/851; H10W72/874; H10W72/884; H10W90/00; H10W90/701; H10W90/731; H10W90/736; H10W90/751; H10W90/756
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
87 words
A semiconductor device in which a semiconductor chip is fixed to a base by a solder material layer made of an alloy containing tin and copper, wherein a first metal layer consisting of a member selected from the group consisting of titanium, chromium, vanadium, zirconium, niobium, and an alloy containing not less than 75 atomic % of at least one thereof is interposed between said solder material and said semiconductor chip so as to have a thickness falling within a range between 2,000 Å to 3 μm.
Claim 2
Dependent Claim
87 words
A semiconductor device in which a semiconductor chip is fixed to a base by a solder material layer made of an alloy containing tin and copper, wherein a first metal layer consisting of a member selected from the group consisting of titanium, chromium, vanadium, zirconium, niobium, and an alloy containing not less than 75 atomic % of at least one thereof is interposed between said solder material and said semiconductor chip so as to have a thickness falling within a range between 2,000 Å to 3 μm.
Claim 3
Dependent Claim
25 words
A device according to claim 1, wherein said first metal layer consists of a metal selected from the group consisting of titanium, chromium and vanadium.
Claim 4
Dependent Claim
31 words
A device according to claim 1, wherein said first metal layer contains not less than 75 atomic % of a metal selected from the group consisting of titanium, chromium and vanadium.
Claim 5
Dependent Claim
24 words
A device according to claim 1, wherein a thickness of said first metal layer falls within a range between 2,300 Å and 1 μm.
Claim 6
Dependent Claim
27 words
A device according to claim 1, wherein said solder material layer further contains not more than 53 atomic % of zinc based upon a content of copper.
Claim 7
Dependent Claim
27 words
A device according to claim 1, wherein said solder material layer further contains not more than 25 atomic % of aluminum based upon a content of copper.
Claim 8
Dependent Claim
19 words
A device according to claim 1, wherein said solder material layer contains 13.3 to 75 atomic % of copper.
Claim 9
Dependent Claim
60 words
A device according to claim 1, wherein a second metal layer consisting of a member selected from the group consisting of nickel, cobalt and an alloy containing not less than 75 atomic % of at least one thereof is interposed between said first metal layer and said solder material layer so as to be thinner than said first metal layer.
Claim 10
Dependent Claim
33 words
A device according to claim 1, wherein said first metal layer further contains not more than 20 atomic % of at least one element selected from the group consisting of phosphorus and boron.
Claim 11
Dependent Claim
23 words
A device according to claim 1, wherein the thickness of said solder material falls within a range between 0.5 μm and 5 μm.
Claim 12
Dependent Claim
23 words
A device according to claim 1, wherein an antioxidant layer made of gold is interposed between said solder material layer and the base.
Claim 13
Dependent Claim
23 words
A device according to claim 11, wherein the thickness of said gold layer falls within a range between 500 and 3,000 Å .
Claim 14
Dependent Claim
16 words
A device according to claim 1, wherein said first metal layer comprises a plurality of layers.
Claim 15
Dependent Claim
33 words
A device according to claim 1, wherein said second metal layer further contains not more than 20 atomic % of at least one element selected from the group consisting of phosphorus and boron.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-09-03 | 1994-03-05 | 1994-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-03 | 1998-03-05 | 1998-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-03 | 2002-03-05 | 2002-09-04 | $7700.00 | Window Closed / Lapsed |